Thermal Analysis Kinetics Of LLDPE, PP/Mine Derivative And Nano-Powder Composites

Polyolefin is composed of olefin monomer, and it is a polymer resin system which hasmass production and great demand. Main varieties are polyethylene, polypropylene andpolyisobutylene. Blending and compounding can make polyolefin higher performance andfunctionallization, and the research around the polyolefin has important theoreticalsignificance and application value.The nonisothermal crystallization and thermal degradation of different contents of FlyAsh, Coal Gangue, Red Mud atc mineral derivational powder and POSS, Nano-CaCO₃filledin linear low density polyethylene（LLDPE） and polypropylene（PP） composites wereinvestigated by using differential scanning calorimetry （DSC） and thermogravimetricanalysis（TGA）. The nonisothermal crystallization behavior of various types of compositeswas investiged using Ozawa method, Avrami equation modified by Jeziorny and Mozhishenmethod. And diffusion activation energies of compoosites during nonisothermalcrystallization were determined by Kissinger method. Kinetics of thermal degradation ofcomposites was evaluated by two different techniques: Kissinger （differentiation method） andFlynn-Wall-Ozawa （integration method） method.Jeziorny and Mo zhi-shen method can describe the crystallization behavior of variouspowders doped with LLDPE or PP blends, and conclusions are consistent. But the Ozawamethod is not suitable for treatment. The blends’ thermal degradation were shown as a singleweight loss stages of degradation process, and the change trend of activation energycalculated by Flynn-Wall-Ozawa and Kissinger methods is basically the same.Fly Ash maked LLDPE crystallization rate changes.While adding20-25wt.%Fly Ash,LLDPE’s crystallization rate reach minimum. And Fly Ash reduces crystallization rate of PP.Addition of Fly Ash could low migration activation energy of crystallization of LLDPE andPP and promote the formation of crystal nucleus. The heat stability of LLDPE first decreasesand then increases as the content of Fly Ash adding. Apparent activation energy ofLLDPE/Fly Ash（10wt.%） composites thermal degradation was reduced to minimum value 28.31percent contrast with the pure LLDPE. Addition of Fly Ash could improve the thermalstability of PP blend system to some extent, and apparent activation energy reached amaximum253.29kJ/mol as Fly Ash content is5wt.%.Coal Gangue maked LLDPE and PP crystallization temperature higher at the samecooling rate. Coal Gangue contributed to low crystallization rate constant of LLDPEcomposites, and crystallization rate constant reached minimum as Coal Gangue content is15wt.%. Crystallization rate of PP composites appeared to have a decline trend after an initialascent with the content of Coal Gangue increasing, and it reached a peak while Coal Ganguecontent is15wt.%. Coal Gangue maked LLDPE or PP maximum weight loss rate temperaturerisen markedly. Apparent activation energy of LLDPE composites changed with the content ofCoal Gangue increasing, and it reached a maximum（12.15%higher compared to pure LLDPE）as Coal Gangue content is10wt.%. Apparent activation energy of LLDPE composites hasbeen noticeably improved because of the addition of Coal Gangue.The addition of vinyl-polyhedral oligomeric silsesquioxane（V-POSS） lowered peaktemperature of PP’s crystallization, while the addition of octyl-polyhedral oligomericsilsesquioxane（O-POSS） made peak temperature of PP’s crystallization higher. Both V-POSSand O-POSS had only a limited influence over crystal nuclei forming and growingmechanism of PP, and caused activation energy of crystallization increased. Thermal stabilitywas higher to some extent because of the addition of V-POSS or O-POSS, while V-POSS hadbetter efficacy.Nano-CaCO₃maked LLDPE crystallization temperature higher, and loweredcrystallization rate constant Zc. It reached a minimum while Nano-CaCO₃content is10wt.%.The addttion of Nano-CaCO₃caused activation energy of crystallization decreased. It madeLLDPE starting degradation temperature Toand maximum weight loss rate temperature Tmincreased, to improve the thermal stability of system. Apparent activation energy of thermaldegradation changed with the increasing of Nano-CaCO₃content. And it reached a maximumin the10wt.%, while is124percent of pure LLDPE.All of this work can push the subject of blending modification forward and guide industrial production.